This paper analyzed in-service teacher professional development such as instructional
consultation, instructional supervision, and class criticism from the perspective of Cultural
Historical Activity Theory (CHAT). For doing so, criteria questions were elicited in order to
distinguish three activities and an attempt was made to explain the relationship between
three activities both synchronically and diachronically. The perspective of cultural historical
activity theory posits the need to consider the unit of teacher professional development as
community-based learning and development in which dialogues on classroom instruction
occur rather than individual-based one. In this perspective, the possibility of change in roles
and consensus on artifacts and rules are the key criteria questions for exploring the
characteristics and meanings of teacher professional development activities. In the
diachronical sense, the gap in time when each activity was introduced exist, and it can be
understood that new activity appeared in order to tackle the issues of the existing activity
systems. And in this process, expansive learning has occurred by modifying and expanding
the elements of activity systems of teacher professional development as new questions arose.
In the synchronical sense, it was seen that conflicts still exist within the three systems in
that their distinct rules and division of labor are being applied to the teacher community in
multilayered ways.